1. Field of the Invention
This invention relates to materials used in the treatment of pet and animal excretions. Specifically, this invention relates to materials that enable the convenient and effective treatment of cat, dog, and other animal excretions.
2. Description of the Prior Art
Sand has traditionally been used in the treatment of pet and other animal excretions. Sand is spread in the animal's cage or litter box and replaced after the animal deposits its excretions there. This is an inconvenient method, however, because pieces of sand containing animal excretions are scattered outside of the intended area when the animal enters and leaves the cage or litter box. For this reason, there have been recent attempts to find materials that readily absorb liquids and that have granules, which, after absorbing liquid, readily adhere together to form into clumps, thereby inhibiting the scattering of particles and enabling easy disposal.
Testing has been conducted on methods of using bentonite and other crushed clayey minerals; starch, CMC, and other viscous substances; water-absorbent resins; and other means of meeting the requirements. In particular, there have been recent studies on a variety of materials that employ water-absorbent resins. Known examples include a product obtained by mixing zeolite particles and other inorganic particles with specific amounts of water-absorbent resin and water, then granulating the mixture (Japanese Patent Application Laid-Open No. 108927/1989); a material obtained by granulating, then drying, a composition derived from paper-making residue, water-absorbent resin, and water-soluble inorganic salts (Japanese Patent Publication No. 6767/1991); and a material obtained by granulating a composition derived from natural organic substance, water-absorbent resin, and a binder (JP-B-46089/1991).
However, materials using bentonite or other crushed clayey minerals or using starch, CMC, or other viscous substances are slow to absorb excretions and absorb only small quantities. The result is that the excretions work its way to the bottom of the cage or litter box and soils it, or spreads out horizontally, not allowing sufficient clumping together of the granules. Problems also occur when the surface of the material becomes sticky and adheres to the animal's paws or fur. Testing was conducted on reducing the diameter of the granules (to 1-2 mm), in an attempt to improve absorbing speed. While a small improvement in absorbing speed was achieved, the granules were so small that they slipped up and under the nails of the pets and other animals, only to fall out after the animals left the cage or litter box, soiling the room and creating a new problem. The ability to absorb liquid is improved by using granulated materials made by combining water-absorbent resin with either inorganic granules, paper-making residue, natural organic matter, or other materials. However, these components swell as they absorb liquid, resulting in the granules of water-absorbent resin either becoming detached or disintegrating, which, in turn, renders it difficult for clumps to maintain their shape.
An even more detailed explanation reveals that although pulp has a high water-absorbency speed, its specific gravity is so low that it sticks to the paws and fur of pets, after which it soils the room. It would seem easy to solve this problem by adjusting the overall specific gravity of the resultant material by combining pulp with an inorganic substance having a higher specific gravity. Pulp is not easily granulated, however, when combined with inorganic substance alone. This brings up the question of employing a binder. Using acrylic resins, butyl rubber, and other synthetic resins or synthetic rubbers does enable easy granulation, but the material obtained from these processes has a slow water-absorption speed. Adding starch, CMC, or other natural high-molecules or water, then granulating the composition, does prevent a large reduction in water-absorption speed, but the grains that have absorbed the liquid will not clump together.